PAP,
I take about 200' of mono off of my rigger rods and attach 30# flea flicker with a blood knot. You really only need the flea flicker for the amount of line that will be in the water while trolling. The down side is that the 30# FF line twists up easily but it doesn't seem to affect the strength. When you tie the two lines together, make sure the flea flicker snugs down VERY WELL (It's oblong in shape). It's not round line and knots can be difficult to get real tight. You'll see what I mean when you get it. I lost a real screamer last year when it ran out all of my FF and mono and I needed to tighten down on the line and the knot gave way. I still dream about that fish! Try Cold Water Tackle for the FF.
http://www.coldwatertackle.com/cortland-flea-flicker-monofilament-fishing-line